In an image forming apparatus, an electrostatic latent image can be formed on a photoconductor, and developed into a visible image using toner. The visible toner image can be transferred to a printing medium. Formation of an image is completed when the toner image transferred to the printing medium is fixed to the printing medium.
A fusing device can be adapted to apply heat and pressure to a printing medium to fix a toner image to the printing medium. Such a fusing device can include a heating roller to apply heat to the printing medium and a press roller to apply a predetermined amount of pressure to the printing medium. When the printing medium passes between the heating roller and the press roller, the toner image is fixed to the printing medium.
An application of voltage to the press roller of a fusing device is known to achieve some improvements in the quality of the resulting image. That is, because the toner image of the printing medium delivered to the fusing device may exhibit an electrical charge of certain polarity, a voltage may be applied to the press roller to charge the press roller with a polarity opposite to the polarity of the toner image in order for a larger proportion of the toner to be fixed on the printing medium.